choosing the right load cell - alliantech bending beam miniature s type single point weighbeam...

1

CHOOSING THE RIGHT LOAD CELL

2

Bending Beam

Miniature

S Type

Single pointweighbeam

BendingBeam

BendingBeam

Diaphragm

Clevis Pin

Diaphragmpancake

Cannister

MultipleColumn

SingleColumn

Column

Shearpancake

Donut

Donut

ShearBeam

Diaphragm Column

Types of Load Cells

3

Scientific weighing

Process Weighing

Industrial weighing

Specialist ForceMeasurements

Retail weighing

Test &Measurement

Research/CalibrationForce measurement

OEM

Main Focus

Oil & Gas

Some Customers

Main Focus

Application Segments

4

INDUSTRIAL W EIGHING

FORCEMEASUREMENT

RETAILW EIGHING

OFFICEW EIGHING

Application Segments

5

Tension

Compression

Principle of the Load Cell

6

10V


7

10V

LOAD


8

How a Load Cell is Constructed

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10


11


12


13


14


15


16


17


18


19


20


21


22


23


24


25

Compression Tension


26

Elements of a Load Cell

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28


29

Unique Load Cell Characteristic

Load Cells form part of the structure that they are measuring

30

Load Cell Specifications

Connection to structure

Measurement Type

RangeTemperature Range

Electrical Connection

Size

Accuracy

Environmental

Excitation

Weight

Overload protection

Signal O/PMounting considerations

Extraneous Loads

Sensitivity

Additional O/Ps

Internal External

Connection to measurement

system

Sensor Properties

31

• So many combinations of specs are mutually

exclusive: Specifying a load cell is trading one

performance criteria against another.

– Example Pick 3 and you compromise the fourth

• High load capacity

• Small size

• High accuracy

• Immunity to extraneous loads

Specifying a Load Cell

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Mounting

33

Mounting

34

Mounting

35

Mounting

36

Mounting

37

Mounting

38

Mounting

39

Mounting

40

Mounting

41

Mounting

42

Mounting

43

Mounting

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Mounting

45

Mounting

46

Mounting

47

Mounting

48

Mounting

49

Mounting

50

Mounting

51

Load Range

Usually same as load range

OverloadRange

ProgressiveDamage

Mechanical failure

Load Range

52

10,000 100,000 1,000,000 Lbs1,000100100Load Range

Model 41

Model 75

Model 46

Model 45

Model UG

Model 31

Model 34

Model 11

Model RGM, RGH, RGF

Model RM, RH, RF

Model 81

Model 82

Model TH

Model 53

Model D

Specials

Model TG

Model 43

Model 73

Model MPB

Model 13

Model LFH-71

250 15000 50000 5000005 50

CompressionFatigue rated version

Tension BendingTension & Compression

Fatigue rated version

Model WG

Load

Ran

ge

Load Range

53

TENSIONCOMPRESSION

Model 41

Model 11

Model 75

Model 31 Model 34

Model RGM,RGH,RGF

Model 47 Model 49

Model UG

Model 81

Model RM,RH,RF

Model 82

Model LFH-71

Model 73

Model MPB Model 13

Model TG

Model MBL Model 43

Model TH Model 53 Model D

Model WG Model GR Model SP

Accuracy

54

100,000 lbs 10,000 lbs 1,000 lbs 100 lbs 10lbs

TENSION/COMPRESSION

COMPRESSION

TENSION

Model UG 0.03%0.02%0.03%0.02%Model 470.03%0.02%0.03%0.02%Model 49Model 41 Model 75

Model TG Model M PBModel WG Model 73Model TH

0.03%0.02%0.03%0.02%Model 47

Model 75Model 410.03%0.02%0.03%0.02%Model 49

Model RGM,RGH,RGFModel 31

Model WG Model 73Model 4310,000 lbs Model 73Model 73

Model MPB Model THModel MPB Model 53Model LFH-71Model D

Model RM,RH,RFModel 82 Model 82 Model 82 Model 81

Model UG0.03%0.02%0.03%0.02%Model 470.03%0.02%0.03%0.02%Model 49

Model 75Model 41

Model RGM,RGH,RGF

Model 34Model 31

Model LFH-71Model 43Model 13Model 73

Model 11

Model DModel 53

0.03%0.02%0.03%0.02%Model 490.03%0.02%0.03%0.02%Model 47Model UG

Model 41Model 75Model 31Model 34Model 11

Model 13 Model 13 Model 43Model 73 Model DModel 53 Model LFH-71

Model 41

Model 34Model 31Model 11

Model 13Model 43

Model DModel 53

Model 43

Model UG

Model RM,RH,RF

100,000 lbs 10,000 lbs 1,000 lbs 100 lbs 10lbsTE

NSIO

N/C

OM

PRESSIO

NC

OM

PRESSIO

NTE

NSIO

N

Model UG

0.03%

0.02%

0.03%

0.02%

Model 47

0.03%

0.02%

0.03%

0.02%

Model 49

Model 41

Model 75

Model TG

Mod el M PB

Model WG

Model 73

Model TH

0.03%

0.02%

0.03%

0.02%

Model 47

Model 75

Model 41

0.03%

0.02%

0.03%

0.02%

Model 49

Model RGM,RGH,RGF

Model 31

Model WG

Model 73

Model 43

10,000 lbs

Model 73

Model 73

Model MPB

Model TH

Model MPBModel 53

Model LFH-71Model D

Model RM,RH,RFModel 82

Model 82 Model 82 Model 81

Model UG

0.03%

0.02%

0.03%

0.02%

Model 47

0.03%

0.02%

0.03%

0.02%

Model 49

Model 75

Model 41

Model RGM,RGH,RGF

Model 34

Model 31

Model LFH-71

Model 43

Model 13Model 73

Model 11

Model DModel 53

0.03%

0.02%

0.03%

0.02%

Model 49

0.03%

0.02%

0.03%

0.02%

Model 47

Model UG

Model 41

Model 75

Model 31

Model 34

Model 11

Model 13Model 13

Model 43

Model 73

Model DModel 53

Model LFH-71

Model 41

Model 34

Model 31

Model 11

Model 13

Model 43

Model DModel 53

Model 43

Model UG

Model RM,RH,RF

Physical Size

55

Stress Levels

Reduced below

non-fatigue

Rated load cells

-Lower sensitivity

High stress

points reduced

by strain gage

placement to

highest stress

area. Structure

cross sections

increased

Fatigue rated to 1000 million cycles compared to 1 million cycles

Fatigue Rating

56

OFF AXIS LOADINGTORQUE

SIDE LOADING

Extraneous Loading

57

Pancake Style load cells

have excellent off axis

immunity

Typically 20% side load

gives less than x% error

Pancake design

Extraneous Loading

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Poor off axis

performance due to

dimensional geometry

Miniature design

Distance from centerline to gauges

Distance from centerline to gauges

Extraneous Loading

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The larger the width to

height ratio the higher

the immunity to side

load

Column design

Poor Better Good Best

Extraneous Loading

60

Multiple column

cells can reduce

effects of off axis

loading

Column design

Extraneous Loading

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Column design

Multiple column

cells can reduce

effects of off axis

loading

Extraneous Loading

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S Beam designs are

poor in side loading

immunity and therefore

poor in compression

S Beam design

Extraneous Loading

63

The use of load

cells in tension

and with rod end

bearings

eliminates side

loading

S Beam design

Extraneous Loading

64

Load Cells

Pancake

Product Range

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Load Cells

Pancake Miniature

Product Range

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Load Cells

CannisterPancake Miniature

Product Range

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Load Cells

CannisterPancake Miniature DonutStyle

Product Range

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Load Cells

CannisterPancake Miniature DonutStyle

Rod EndStyle

Product Range

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Load Cells

CannisterPancake Miniature Z BeamDonutStyle

Rod EndStyle

Product Range

70

Load Cells

CannisterPancake Miniature Z BeamDynamic

Load

DonutStyle

Rod EndStyle

Product Range

71

Load Cells


Load

DonutStyle

Rod EndStyle

Special Applications

Product Range

72

Load Cells


Load

DonutStyle

Rod EndStyle


TensionCompression

TensionCompression

Compressiononly

Compressiononly

Ultra HighPrecision

Ultra HighPrecision

Fatigue Rated

Non-Fatigue Rated

0.03%

0.03%

0.02%

0.02%

0.03%

0.03%

0.02%

0.02%

Model 47

Model 45

Model 75

10,000 lbs

Model 73Model 73

Model 41

Model 460.03%

0.03%

0.02%

0.02%

0.03%

0.03%

0.02%

0.02%

Model 73Model 43

Model 49

Product Range

73

Load Cells


Load

DonutStyle

Rod EndStyle


Tension/CompressionMale thread

Tension/CompressionFemale Thread

Low Cost Compression Only

TensionCompression

Compressiononly

High CapacityCompression

MiniatureSubminiature

Model 31

Model 34

Model 53

Model 13

Model 11

Model LFH-71

Product Range

74

Load Cells


Load

DonutStyle

Rod EndStyle


Compression Only

Tension &Compression

100 to 200,000 lbs0.03%

Model UG

15,000 to 3,000,000 lbs0.25%

10,000 to 500,000 lbs0.03%

50,000 to 500,000 lbs0.1%

Model WG

Model MPB

Model TGModel TG

Product Range

75

Load Cells


Load

DonutStyle

Rod EndStyle


150 grms to 30,000 lbs

15,000 to 200,000 lbs

Compressiononly

Model TH

Model D

Product Range

76

Load Cells


Load

DonutStyle

Rod EndStyle


Male-MaleThread

Male-MaleThread

Male-FemaleThread

Male-FemaleThread

Female-FemaleThread

Female-FemaleThread

TensionTension

Compression

Model RGM

Model RM

Model RGH Model RH

Model RGF Model RF

Product Range

77

Load Cells


Load

DonutStyle

Rod EndStyle


100-20,000 lbs

TensionOnly

5-250 Lbs

Model 82 Model 81

Product Range

78

Load Cells


Load

DonutStyle

Rod EndStyle


10,000 lbs1000 lbs

Model DLN Model DLS

Product Range

79

Load Cells


Load

DonutStyle

Rod EndStyle


Clevis Pins

Build fromscratchspecial

Single PointCompression

Product Range

80

Load Cells


Load

DonutStyle

Rod EndStyle


Clevis Pins

Build fromscratchspecial

Single PointCompression

StandardProduct

Specials

Product Range

81

INDUSTRIAL WEIGHING

FORCEMEASUREMENT

RETAILWEIGHING

OFFICEWEIGHING

Market Segments: Weighing

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– Fast Response

– Long fatigue life

– Large temp range

– Majority: Industrial

– Minority:Hostile

– Low compliance

– Low to medium volume

– Medium to high

accuracy

– NIST traceable

– DC response

– Low cycle life

– Limited temperature range

– Majority: room environments

– Minority: salt and water

– Large deflections

– High volume

– High accuracy

– Low cost

– ‘Legal for trade’

Force Weighing

Market Segments: Weighing vs Force Measurement

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Difficult to seal

Environmental

84

Barometric pressure

Single sided diaphragm

Hermetically sealed

50 lb canister example

Environmental

85

Barometric pressure

Barometric pressure

Diaphragm eachside equalizes

pressure effects

Environmental

86

High temp

connector

High temp

strain gages

High temp

solder

Aluminum only good to 120 F

Stainless good to 500 F

Environmental

87

350 ohm

bridge with

mV/V output

Amplified output

0-5V

0-10V

4-20mA

Note: Miniature and high temperature load

cells do not have amplified outputs

Electrical

88

Signal +ve

Ground

Supply +

2 mV/V

Signal = 20 mV maximum Noise = 1 mV

Signal to noise ratio = 20

(Digitizer error as much as 10%)

Noise Immunity

89

Signal +ve

Ground

Supply +

15-32 V DC Supply

0-10V output

Internal amplifierfitted

Noise Immunity

90

Signal +ve

Ground

Supply +

0-10V

Signal = 10 V maximum Noise = 1 mV

Signal to noise ratio = 10,000

(Digitizer error only 0.01%)

Noise Immunity

choosing the right load cell - alliantech bending beam miniature s type single point weighbeam...

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